For man, autumn is a time of harvest, of gathering together.
For nature, it is a time of sowing, of scattering abroad.
~Edwin Way Teale
|Ash tree in front yard|
|Ash trees in back yard &|
at house across the street
|River birch in foreground|
|Pee Gee Hydrangea|
|Pee Gee hydrangeas in background|
behind Black-eyed Susan & sedum
|Golden Raindrops Crabapple|
|Blue muffin viburnum & Korean Pear|
|Hawthorn & Tiger Eyes Sumac|
|Witchhazel & Baptisia|
There is concern climate change may pose a threat to these spectacular fall colors many of us look forward to viewing as winter approaches. Warmer weather is contributing to a later ending to the growing season in the U.S. according to research from Seoul National University. The end of the growing season (when the overall greenness of foliage starts to decline as seen by satellite) was over two weeks later in 2008 compared to 1982.
Cool fall nights and decreasing day lengths are a signal to trees manufacture anthocyanins, the red pigment that colors fall leaves. If nights remain hotter as the climate warms, this process may be disrupted, resulting in less colorful foliage. If droughts become more pervasive, as many climate change models predict, stressed trees may simply shed their leaves early without the color change. Climate change might eventually make conditions unsuitable for trees such as sugar maples, forcing them to migrate north to survive. None of the more southerly species that might move in to replace them have the brilliant fall colors that maples display. A lengthening growing season might also open up the door for invasive species, particularly invasives that are adaptable to different climate.